It's alright! There are a lot of other members here who are marketing, and sharing their ideas. You can contact them and ask for assistance, or even create a journal here in the group asking for help/aid/advice.
I believe that you can start advertising now, it seems you have enough pages. I was told that it's possible to start after 10 pages, but having around 30 can make it so new readers get hooked!
I've done the convention thing for nearly 10 years now, and it's awesome, but, yeah, it takes practice. I've somehow learned how to go an entire day without using the bathroom, or eating, but I don't recommend it, it's not healthy. If you choose to do one, I suggest going in with someone else! Share a booth. It halves the cost, draws more people over, and both of you are able to take turns taking breaks. To sell at a convention, I'd suggest having a few copies of your comic, and other things... such as pinback buttons, necklaces, stickers, etc. especially fan art related items! Sell them for a profit, and include a business card linking to your comic online with every purchase. Also, walk around before the artist alley opens. Talk to other artists! Trade business cards, and even trade artwork, this helps you gain friends who help you out. Doing commissions, selling additional items, handing out cards, it all helps
I'd say print out flyers for the comic, showing the art and the skill level in it, as well as the detail, and pass those out. Any extras? Drop them off at a local comic book store!
You always lose fans when you switch from a fan media, to an original. It just happens, but don't fret! I was in the same boat, but you CAN draw back the crowd! Fan material is always very popular... often ridiculously so, but you can use that to your advantage. I've seen people at conventions drawing fanart... on flyers. The back of the flyer told all about their original character story. It was brilliant, people purchase the art because they loved it, so they made back the cost of the flyer being printed, and made a profit, while also ensuring no one tossed it out, and would learn about the story.
You can do it! There are lots of members here who will help!